School of Sport, University of Stirling, Stirling, Scotland.
Int J Sport Nutr Exerc Metab. 2011 Dec;21(6):492-500. doi: 10.1123/ijsnem.21.6.492.
This study assessed fluid balance, sodium losses, and effort intensity during indoor tennis match play (17 ± 2 °C, 42% ± 9% relative humidity) over a mean match duration of 68.1 ± 12.8 min in 16 male tennis players. Ad libitum fluid intake was recorded throughout the match. Sweat loss from change in nude body mass; sweat electrolyte content from patches applied to the forearm, calf, and thigh, and back of each player; and electrolyte balance derived from sweat, urine, and daily food-intake analysis were measured. Effort intensity was assessed from on-court heart rate compared with data obtained during a maximal treadmill test. Sweat rate (M ± SD) was 1.1 ± 0.4 L/hr, and fluid-ingestion rate was 1.0 ± 0.6 L/hr (replacing 93% ± 47% of fluid lost), resulting in only a small mean loss in body mass of 0.15% ± 0.74%. Large interindividual variabilities in sweat rate (range 0.3-2.0 L/hr) and fluid intake (range 0.31-2.52 L/hr) were noted. Whole-body sweat sodium concentration was 38 ± 12 mmol/L, and total sodium losses during match play were 1.1 ± 0.4 g (range 0.5-1.8 g). Daily sodium intake was 2.8 ± 1.1 g. Indoor match play largely consisted of low-intensity exercise below ventilatory threshold (mean match heart rate was 138 ± 24 beats/min). This study shows that in moderate indoor temperature conditions players ingest sufficient fluid to replace sweat losses. However, the wide range in data obtained highlights the need for individualized fluid-replacement guidance.
本研究评估了 16 名男性网球运动员在室内网球比赛（17 ± 2°C，42% ± 9%相对湿度）中的液体平衡、钠流失和运动强度，平均比赛持续时间为 68.1 ± 12.8 分钟。在整个比赛过程中记录了随意的液体摄入。通过裸体体重的变化来测量汗液流失；通过贴在前臂、小腿和大腿以及每个球员背部的贴片来测量汗液电解质含量；通过汗液、尿液和日常食物摄入分析来测量电解质平衡。通过与最大跑步机测试获得的数据相比，从场上的心率评估运动强度。出汗率（M ± SD）为 1.1 ± 0.4 L/hr，液体摄入率为 1.0 ± 0.6 L/hr（补充了 93% ± 47%的流失液体），导致体重仅平均下降 0.15% ± 0.74%。注意到出汗率（范围 0.3-2.0 L/hr）和液体摄入（范围 0.31-2.52 L/hr）的个体间差异很大。全身汗液中的钠浓度为 38 ± 12 mmol/L，比赛期间的总钠流失量为 1.1 ± 0.4 g（范围 0.5-1.8 g）。每日钠摄入量为 2.8 ± 1.1 g。室内比赛主要包括低于通气阈值的低强度运动（平均比赛心率为 138 ± 24 次/分钟）。本研究表明，在中等室内温度条件下，运动员摄入了足够的液体来补充汗液流失。然而，获得的数据范围广泛突出了个性化液体补充指导的必要性。
